Sub pages menu on wordpress

header.php

 <?php

        if (isset($cat) && !empty($cat)) : ?>

            <nav role="category-navigation">

                <a href="#" id="dropdown-menu"><?php _e('Menu', 'dwframework'); ?></a>


                <?php

                // Query the lasts ten category posts
                $category_ten_last_posts = array(
                    'numberposts' => 10,
                    'cat' => $cat,
                    'orderby' => 'date',
                    'order' => 'DESC'
                ); ?>

                <div class="menu-menu-1-container">
                    <ul id="menu-category-1" class="menu">
                        <?php foreach (get_posts($category_ten_last_posts) as $post) : ?>
                            <li class="menu-item menu-item-type-custom menu-item-object-custom">
                                <a href="<?php echo get_permalink($post->ID); ?>"><?php echo $post->post_title; ?></a>
                            </li>
                        <?php endforeach; ?>

                    </ul>
                </div>
                <div class="clearfix"></div>
            </nav>

        <?php endif; ?>